Generator of electrical oscillators of high frequency



M. R; GAVIN Feb. 12, 1946.

GENERATORS OF ELECTRICAL OSCILLATORS OF HIGH FREQUENCY Filed Jan. 2, 1942 on 1 CATH E L CA'THODE 1 Patented Feb. 12, 1946 i UNITED STATES A PATENT OFFICE GENERATOR OF ELECTRICAL oscrtm'rohs OF HIGH FREQUENCY ,7

Malcolm Ross Gavin, Wembley, England, assignor 7 q to The General Electric Company Limited, Londo nEngland i 1 a Application January 2, 1942, Serial No. 425,429

' I iLGreat Britain November 5, 1940 7 Claims; (Cl. 250- 36) TIThisinvention relatesto electrical oscillators, ing broadly,theconnection between the two adapted to generate oscillations of high frequenvalves in Figure 2 is cut ofi;1the electr cal length cy, of the type comprising a pairof thermionic of each remaining stump of .the concentrlcjlne grid-controlled valves operated in push-pu ll and d,-f.5 has now to be M2.. T e t e ends of feedlnga resonant circuitof which at least part stumps (4, 5), (4', 5") 'may emerge from the enconsists of a concentric line. velopes l4, l4 as in Figure 3 or may be con- Two known oscillators of this type are shown tained within the envelopes as in Figure 4. The diagrammatically in Figures 1 and 2 respectively grid lead is branched; the end of eachbranch of the accompanying drawing. Figures 3 and 4 is attached to a tube or rod 4, 4', preferably at show diagrammatically two embodiments of the 10 a point at an electrical distance M4 from its free invention. end as shown in Fig. 4. If these points lie with- In Figure 1, a pair of triodes, each consisting in the envelopes, but another part of the line hes of a cathode l or I, a concentric grid 2 or 2', outside the envelope, it may be desirable to attach and a concentric anode 3 or 3', are connected to the grid lead at a point outside the envelope which the opposite ends of a straight concentric line, 5 is not a node; this can be done if, as indicated consistingof inner conducting tube or rod 4 and in Fig. 3 chokes l3, l3 are inserted between the outer conducting tube 5. The electrical length common part of the lead l0 and the ends of the of the line is M2, where A is the wave-length of branches attached to the tubes or rods 4, 4.

the oscillations. Each cathode lead 6 or 6 is the The leads for heating the cathode can be arinner member of another concentric line Whose 0 ranged as is usual in the arrangement shown in outer member is I or 1'; I and I are connected Figur 2- The le ds 6, 6' each consist of a p by the screen 8 surrounding the line 4, 5; the of concentric conductors insulated from each cathode leads are tuned by means of the bridges other; one end of the heating element [1, I1 is 9, 9. The anode supply lead H can be attached connected to the outer member and the other to any point on the tube 5, since this conductor to the inner member. The parts shown in Figis grounded for high frequency oscillations; the ure 3 or 4 may be surrounded by a screen (not grid is fed by a lead I0 attached to the electrical shown) performing e m function as the centre of the tube or rod 4 and passing through screen 8 in Figure 1.

a holein conductor 5, According to the invention, an electrical oscil- In this oscillator the two cathode leads have to to o t e typ ec fi w in t e said v e be tuned separately. In order to avoid thi inare arranged side by side and so that their cathconvenience the modification shown in Figure 2 ode ds m a par l li e t rmina le by has been used. Here thelconcentric line 4, 5 has means of a brid Comprises a p r of ncenbeen bent round so that the cathode leads emerge tric lines, One connected to he grid and no side by side; they then form :a parallel line which of one said v lve nd he oth r conne ed to th can be tuned by the bridge [2. grid and anode of the other said valve, the said But now a lower limit is set to thelength of lines each being O at the end remote from e concentric line 4, 5 and therefore, sinc this the cathode of the valve with which it is associlength is about M2, an upper limit is set to the ated and the electrical length of each said line possible frequency of the oscillations generated. 40 being substantially M2, where A is the wavelength (It is to be observed that since the system is an of the oscillations that the oscillator is adapted oscillator, it is difficult to prevent it from oscillatto generate. mg in its fundamental mode; the possibility of What I claim as new is: the lengths being a multiple of M2 is excluded.) 1. A high-frequency electrical oscillator com- Furthermore the electrodes of the valves will be prising a pair of thermionic grid-controlled valves 811010566- n enve pes l4, The line must operating in push-pull, wherein the said valves be long enough to emerge from the envelope and are arranged side by side and their cathode leads to extend over the distance between the electrode form a arallel line terminable by means of a sy t s w n the env l p s ar in ta t- Th bridge, the oscillator also comprising a pair of object of this'invention is to abolish the limit concentric lines, one connected to the grid and set by this consideration and thus to raise the anode of one said valve and the other to the upper limit of the frequency of oscillation. grid and anode of the other said valve, the said Figs. 3 and 4, which show diagrammatically lines each being open at the end remote from the two embodiments of the invention respectively, cathode of the valve with which it is associated indicate how this object may be attained. Speakand the electrical length of each said line being M2, where A is the wave-length of the oscillations that the oscillator is adapted to generate.

2. A high-frequency electrical oscillator according to claim 1 wherein each said open end of a line lies within the envelope of the valve with which it is associated.

3. An electrical conductor according to claim l wherein at least one of the said open ends lies outside the envelope of the valve with which it is associated, wherein a gridlead is attached to a point on one of the said lines that is outside the envelope and is not a node for the oscillations, and wherein the said lead contains a choke.

4. An electrical oscillator according to claim 1 wherein each said cathode lead is a concentric line consisting of a pair of concentric conductors,

and wherein one end of the cathode heater is connected to one member of the pair and the cathode lead is a concentric line consisting of a pair of concentric conductors, and wherein one end of the cathode heater is connected to one member of the pair and the other to the other member of the pair.

-6. An electrical conductor according to claim 1. wherein at least one of the said open ends lies outside the envelope of the valve with which it is associated, wherein a grid lead is attached to a point on one of the said lines that is outside the envelope and is not a node for the oscillations, and wherein the said lead contains a choke wherein each said cathode lead is a concentric line consisting of a pair of concentric conductors, and

wherein one endof the cathode heater is connected to one member of the pair and the other V to the other member of the pair.

7; A high-frequency oscillator according to claim 1 wherein each said thermionic valve is a triode whose anode and grid are cylinders surrounding and concentric with the cathode and are eflectively continuations of the conductors of the said concentric line connected to them.

MALCOLM ROSS vGAV N. 

